A central challenge in the delivery of evidence-based interventions to promote under-five child survival is the coordination of care across the multiple tiers of the health system, from frontline health workers, to primary care clinics, to district hospitals, to specialty providers. Additionally, children who survive or avoid once-fatal diseases such as congenital and rheumatic heart diseases, prematurity, neurodevelopmental conditions, and disabilities sustained from traumatic injuries, are increasingly living well into adolescence, young adulthood, and beyond. Healthcare delivery systems in resource-limited settings, however, are ill- equipped to manage such patients' care. Mobile technologies, coupled with effective management strategies, may enhance implementation and coordination of evidence-based interventions, but few controlled trials exist to validate this. Particularly lacking are strategies that incorporate mobile technologies in an integrated manner across the health system. Intervention: We have developed a mobile health care coordination and quality improvement intervention within two rural district healthcare systems in Nepal, where the child mortality rate is an estimated 82 per 1,000, and coordination of child health care is poor. Firstly the intervention aims to increase the timely engagement in acute care for children under the age of five to receive evidence-based World Health Organization protocols aimed at reducing child mortality-Integrated Management of Pregnancy and Childbirth, Integrated Management of Childhood Illness, Integrated Management of Emergency and Essential Surgical Care, and Community-based Management of Severe Acute Malnutrition. Secondly, the intervention aims to implement a Chronic Care Model for pediatric patients under the age of twenty suffering from a chronic disease (congenital and rheumatic heart disease, diabetes, depression, epilepsy, asthma, musculoskeletal and neurodevelopmental disabilities, and pre- and post-surgical conditions). Analysis: We will conduct a stepped-wedge, cluster randomized controlled trial. The primary outcome of this trial will be under-five mortality. We hypothesize a 25% reduction in under-five mortality rate during the intervention periods, relative to the control period. We hypothesize a 50% improvement in follow-up rates, a 30% improvement in global symptoms score, a 20% reduction in disability score, and a 20% reduction in inpatient days in hospital. We will use both quantitative and qualitative methods to assess the scalability of the intervention in terms of logistics, human resources, costs, and utilization. Impact: Rigorous evaluations of systems-level child healthcare interventions are needed to drive global healthcare policies and their implementation. The trial proposed here will inform the potential impact and scalability of health systems strengthening interventions.